


The Sibling They Never Wanted (But Needed)

by Reioka



Series: Reioka's Tumblr Prompts [10]
Category: Marvel, Marvel Cinematic Universe, The Avengers (Marvel Movies)
Genre: Adopted Sibling Relationship, Fluff and Humor, Gen, Sibling Rivalry, Team as Family
Language: English
Status: Completed
Published: 2017-06-02
Updated: 2017-06-02
Packaged: 2018-11-08 06:48:29
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,321
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11076240
Author URL: https://archiveofourown.org/users/Reioka/pseuds/Reioka
Summary: It seems like the Avengers have to break up a fight between Tony and Natasha at least once a day. Sometimes more. It's kind of hard to believe they'd kill for each other until it happens.





	The Sibling They Never Wanted (But Needed)

**Author's Note:**

> This was a prompt from my Tumblr: Can I request anything showing a tony/natasha friendship? I love the way you write natasha :) Maybe they have the classic sibling relationship where they constantly rag on each other but as soon as someone else tries they shut them down flat? Or whatever really, I'm not picky. Thanks!!
> 
> Bahaha the other Avengers are just along for the ride. Like brother and sister, Tony and Natasha can treat each other like shit, but if someone else treats them like shit, they better get ready to catch hands. (It appears I write this relationship better when there is actually another ship I am supposed to be writing smh.)

The Sibling They Never Wanted (But Needed)

 

“DID YOU USE THE LAST OF MY COCONUT HAIR MASK?!”

 

Steve jumped, clutching his chest. Natasha, who had been playing chess with him, froze like a deer in the headlights.

 

Tony came to a stop in the doorway, looking livid. He had a plastic bottle clutched in one hand. “Did you?!”

 

“…Nnno,” Natasha answered slowly.

 

The brunet let out a screech and lunged for her. “THAT WAS EXPENSIVE AND A TREAT!”

 

Natasha screamed and dove out of her seat. Tony was only a second behind her, flinging the empty bottle at her head. It connected with an empty thunk and bounced off relatively harmlessly.

 

The way Tony continued to chase her around the room, fists clenched like he was ready to beat the shit out of her, was not quite so harmless.

 

“Maybe we should all calm down?” Steve suggested, standing.

 

Tony whipped toward him, wild-eyed. “Steven. Please butt out.”

 

Steve thought he might actually get murdered by a teammate.

 

Natasha tried to skitter past them to the doorway. Tony screamed and leapt on her. She yelped and struggled to keep him from wrapping him hands around her neck.

 

Steve screamed as well and reached out to grab him off of her before he could strangle her or punch her. “Stop it, Tony! Jesus Christ!”

 

“Get off of me!” Tony snarled, squirming. “Natasha that’s two hundred dollars a bottle!”

 

“What!?” Natasha exclaimed, horrified. “That’s way too much!”

 

“It’s a  _treat!_ ” Tony repeated, still trying to escape the blond’s clutches.

 

Steve clutched at him tighter. “Tony, please-!”

 

“TWO HUNDRED DOLLARS!” the brunet shrieked.

 

Natasha fled while she had the chance.

 

.-.-.-.

 

Natasha burst into the brunet’s penthouse, fuming. “You took my  _fucking_  TOVARITCH!”

 

Tony took a sip of said vodka from his glass. “Yes.”

 

“What?” Pepper asked, frowning.

 

“MY TOVARITCH!” Natasha screeched angrily.

 

“I’ll buy you a new fucking bottle,” he scoffed, filling his cup. “Twelve dollars.  _Twelve dollars._ ”

 

Pepper frowned at her glass. “My, this is quite delicious for a twelve dollar bottle.”

 

“It’s my last bottle!” Natasha exclaimed.

 

“Oh, I’m sorry,” Tony snapped back. “It’s almost like going to take a shower and finding someone used the last of your coconut hair mask.”

 

Pepper watched in surprise as Natasha turned on her heel and left the room without another word, then whipped back toward him, shocked. “You mean that really expensive hair mask that you hissed at me for using?!”

 

Tony said nothing but took a long, loud slurp of vodka.

 

“Holy shit,” she breathed. Natasha was lucky she wasn’t dead.

 

.-.-.-.

 

 “I’m going to have a threesome,” Tony declared, making the rest of the Avengers pause in their moping about having to go to the gala.

 

“…What,” Bruce said, because to their knowledge Tony was trying to be better about that type of thing.

 

Natasha snorted, smoothing her dress over her legs. “Well,  _I’m_  going to have a foursome.”

 

“…What,” Clint said, because she typically did not air her business like this.

 

Tony glared at her for a long moment before he replied, “Then I will have an orgy with four other people. And they will all be women.”

 

“Five,” she cut in, smirking. “And they will also all be women.”

 

The brunet was silent for a few minutes.

 

“…Is this a pissing contest?” Steve whispered to Clint, because Bruce looked a little faint.

 

“If it is, it’s the weirdest pissing contest I’ve ever seen,” Clint whispered back.

 

“…I am going to suck every dick at the gala,” Tony began.

 

“NO,” Bruce snarled, making him jump. “Neither of you are having sex with more than one person tonight and you  _will_  be tested tomorrow for STDs!”

 

Tony and Natasha both grimaced with disgust.

 

Neither of them brought anybody home after the gala, though. (They both complained about having to have the tests anyway, but Bruce was adamant.)

 

.-.-.-.

 

Tony reached for the last pancake. Natasha stabbed it with her fork at the same time. They glared at each other.

 

“I got it first,” Tony insisted.

 

“Doubtful,” Natasha scoffed. “Because I got it first.”

 

They glared at each other again, and it was clear that they were about to get into an argument.

 

So Steve reached out and cut the pancake in half. “Oh my God. Share.”

 

They stared at the halves of the pancake before Natasha blurted out, “His half is bigger than mine!”

 

“Nuh-uh!” Tony exclaimed immediately.

 

Clint snatched the pancake from their forks and stuffed both pieces into his mouth.

 

It was worth it to hear Tony’s scandalized screaming about how Clint had promised not to stuff entire pancakes in his mouth anymore.

 

.-.-.-.

 

“So do you and Tony actually like each other?” Steve asked as Natasha helped him pick out some cereal. “Gotta say, I’m getting kind of worried at how often I need to pull you guys off of each other.”

 

“We like each other just fine,” she replied, staring suspiciously at a box of Wheaties with Simone Biles on them. “What a tiny young lady.”

 

“She’s four foot nine. I had a photo shoot with all the Olympians for charity. It’s not just the picture.” the blond answered. “She is  _very_  tiny.”

 

Natasha turned to look at all six-foot-two of him and raised an eyebrow. “You must have felt like a giant.”

 

“Yes,” Steve said. “It was pretty terrifying. Are you avoiding my question?”

 

“No, she’s just tiny,” Natasha replied, dropping the box of Wheaties into the cart. “Tony and I like each other. You can tell, because neither of us is dead.”

 

Steve frowned at her. “You tried to kill him just yesterday.”

 

She rolled her eyes as if he was the dumbest man on earth. It was quite impressive. “Steve, do you actually think that if I wanted Tony dead, he would actually still be alive?”

 

Steve opened his mouth, but nothing came out.

 

“And I know it doesn’t seem like it, but if Tony wanted  _me_  dead, I would be. He’s more cutthroat than a lot of people give him credit for.” She grabbed a box of Lucky Charms and tossed it into the cart as well. “He’s like the brother I never had and sometimes never wanted.”

 

“…You act pretty mean to each other for almost-siblings,” the blond pointed out as she dropped two more boxes of cereal into the cart.

 

Natasha nodded, examining a box of Raisin Bran. “Bucky Barnes picked you up and threw you at one of his attackers.”

 

“…Well, I mean,” he began, frowning. “That’s not the same, really—”

 

“It is in all the ways it matters,” she murmured, dropping the Raisin Bran into the cart as well.

 

Steve sighed. “We do not almost kill each other on a daily basis, Natasha.”

 

“Your feet left the ground, and then he threw you like a fucking shot-put.”

 

.-.-.-.

 

“Ooh,” Tony said happily. “Someone bought me Raisin Bran! Thanks, whoever!”

 

Steve opened his mouth to tell him to thank Natasha, but all that came out was a wounded noise as she kicked him under the table.

 

“It’s because you’re old,” Natasha said.

 

Tony frowned at the box. “Aw. I can’t help it if I want to have regular poops.”

 

Clint choked on his Lucky Charms.

 

Bruce frowned at him severely. “You could stand some roughage as well, Clint. I’ve seen your medical records. Pooping thrice a week isn’t normal.”

 

“Can we not talk about bowel movements at the table?” Steve asked, pained expression now for the content of the conversation and not the ache in his shin.

 

Bruce gave Clint another severe look before returning to his oatmeal and crossword puzzle.

 

“I’ll take some,” Natasha said, holding out her bowl.

 

Tony wrinkled his nose but poured some Raisin Bran into it. “I can’t believe you put milk in your bowl before cereal. That’s weird, Natasha.”

 

“Not as weird as your smoothies,” she retorted, turning back to the table.

 

Tony squawked. “They’re healthy!”

 

.-.-.-.

 

Clint saw Natasha fall under the onslaught from the Doom Bots and couldn’t help the scream it tore from his throat. She was still shooting, but her aim was off, and she couldn’t put any weight on one of her legs. He stood up from his perch, ready to go help—

 

And then there was another scream, one of pure rage, and a red and gold blur came from the sky, straight down into the Doom Bot leading the pack that had been attacking her. The robot exploded outward, and at the bottom of the metal carcass left behind was Tony, repulsors blasting, missiles firing, and holy shit he had a laser canon?!

 

The rest of the flock of robots was summarily fucking decimated. For all the showboating and arrogance that Tony could show, it was easy to forget that in the armor he was basically a walking, talking  _tank._  A tank with a temper, apparently.

 

“How’s she doin’, Tony?” Clint asked when he was certain the robots in their immediate vicinity were down for the count.

_“Broken leg,”_  Tony answered, voice clipped.  _“Probable concussion. Possible dislocated wrist.”_

_“Get her to medical and get back here!”_  Steve barked, and then there was the unmistakable clang of the shield on metal. He added, mostly to himself as if he forgot about the comms,  _“Oh, that’s not good.”_

 

Clint wanted to find him and punch him. “What’s not good?!”

 

There was a long pause, and then,  _“It ate my shield like a piggy bank.”_

 

Tony screeched.  _“Steve!”_

_“It’s fine! It’s fine! I’ll just throw this car at it instead.”_

 

There was a giggle over the comms that was incredibly out of place before Natasha whispered, loudly,  _“Steve’s gonna be in so much trouble with Tony. He **lost**  his  **shield**.”_

_“Steve’s definitely gonna be in trouble with Tony,”_  Tony agreed icily.  _“If he doesn’t fucking get it back. Come on, hon’. I’m gonna take you to medical.”_

 

Clint watched her nod briefly as she allowed the brunet to scoop her up. “And stay in medical for once, would you?!”

 

He saw Natasha stare up at Tony’s golden mask, then reach up to poke where his nose would be.  _“Boop. You should put a nose on your faceplate.”_

_“I will take that under advisement,”_  Tony said dryly, taking to the air.

 

Clint rolled his eyes, unable to help a smile, and shot down three Doom Bots that had been moving to follow them.

 

.-.-.-.

 

Tony burst into the common room with a screech. “I save your ass from Doom Bots and this is the thanks you give me?!”

 

“You have the good pudding,” Natasha drawled, staring at the ceiling. She sucked some pudding from her spoon, then licked the rest off, chewing slowly on the starchy balls in it. “Also it wasn’t me.”

 

The brunet visibly counted to three in his head. “What do you mean it wasn’t you? I see you eating my sago pudding.”

 

“I asked Bruce to get it for me,” she replied, shoving her spoon back into her mouth.

 

Bruce grimaced. “Natasha, why.”

 

“I CAN’T BELIEVE YOU I BUY THAT SPECIAL FROM A SOUTH AFRICAN RESTAURANT YOU FUCKING PLEB!”

 

“’s good,” Natasha said. “Like tapioca. But better. Did Steve ever get his shield back?”

Steve cringed.

 

“NO!” Tony shouted, throwing his hands up. “I have to pry a Doom Bot apart to get it out because  _someone_  decided that the best way to get his shield back was to CRUSH WHAT HAD IT LIKE A SODA CAN.”

 

“I’m sorry,” the blond said weakly.

 

Natasha turned a look on him that probably would have been supremely disappointed in him if it hadn’t been for the painkillers she was on. She threw her spoon at him. Surprisingly, it hit him exactly where she aimed it—right between his eyes.

 

“Ow fuck! Natasha why!?”

 

“You should take better care of your stuff,” she told him, frowning, and used her fingers to eat the pudding instead.

 

“Stop stop stop stop stop oh my God!” Tony exclaimed, grabbing a wad of napkins from the table. “I’ll get you a new spoon. You’re a mess.”

 

Natasha nodded. “I’m a mess.” She flopped her hand about. “But no dislocated wrist.”

 

The brunet took a deep breath, then let it back out in a sigh, smiling a little. “You’re right. No dislocated wrist. Do you want me to order more pudding for you?”

 

“I want,” she began imperiously, then paused. “…I want you to sleep on me.”

 

“Honey, I still have work to do,” he said soothingly. “Can it wait?”

 

She shook her head, patting her lap. “Sleep.”

 

“Natasha, please—”

 

“I made sure to buy Raisin Bran and I even bought organic blueberries for you,” she said, patting her lap again. “Sleep.”

 

Tony’s shoulders shook with a laugh he kept firmly behind his lips as he slowly crawled onto the couch, hovering between her legs. One was covered in a shockingly pink cast. “Okay. You tell me if I start to hurt your leg, okay?”

 

“You weigh, like, a grape,” Natasha informed him, shoving his head down onto her lap. “A small grape. A grape not worth eating.”

 

Tony stared up at her. “…I think that’s the meanest thing you’ve ever said to me.”

 

She frowned at him. “But I would still eat you.”

 

“Just,” the brunet began, then sighed, shaking his head. “Eat your pudding.”

 

“A grape,” she said again firmly, patting his face, then went back to eating the pudding.

 

Clint had to jump to keep it from falling on Tony’s head when she inevitably fell asleep. Thankfully, Tony had dropped off almost immediately after she’d stopped talking to him, because he’d been secretly exhausted.

 

“…Bucky and I are  _not_  like that,” Steve mumbled to himself.

 

“Didn’t he throw you at a few Hydra agents and then when the fight was over bullied you into the medical van?” Bruce asked, frowning.

 

Steve threw his hands up, frustrated. Yes, but he and Bucky did not fight as often as Tony and Natasha.


End file.
